Merge pull request #309 from TomTranter/node_voltages

Node voltages

liionpack/plots.py

@@ -190,7 +190,9 @@ def plot_cells(output, color="dark"):
 
     # Get time and results for battery cells
     time = output["Time [s]"]
-    cell_vars = [k for k in output.keys() if len(output[k].shape) > 1]
+    cell_vars = [
+        k for k in output.keys() if len(output[k].shape) > 1 and k != "Node voltage [V]"
+    ]
 
     context = lp_context(color)
     cmap = lp_cmap(context)

liionpack/solver_utils.py

@@ -377,6 +377,7 @@ def solve(
     nproc=1,
     output_variables=None,
     manager="casadi",
+    node_termination_func=None,
 ):
     """
     Solves a pack simulation
@@ -434,5 +435,6 @@ def solve(
         nproc=nproc,
         initial_soc=initial_soc,
         setup_only=False,
+        node_termination_func=node_termination_func,
     )
     return output

liionpack/solvers.py

@@ -141,11 +141,12 @@ def solve(
         output_variables,
         initial_soc,
         nproc,
+        node_termination_func=None,
         setup_only=False,
     ):
         self.netlist = netlist
         self.sim_func = sim_func
-
+        self.node_termination_func = node_termination_func
         self.parameter_values = parameter_values
         self.check_current_function()
         # Get netlist indices for resistors, voltage sources, current sources
@@ -195,10 +196,14 @@ def solve(
         self.shm_i_app = np.zeros([self.Nsteps, self.Nspm], dtype=np.float32)
         self.shm_Ri = np.zeros([self.Nsteps, self.Nspm], dtype=np.float32)
         self.output = np.zeros([self.Nvar, self.Nsteps, self.Nspm], dtype=np.float32)
+        self.node_voltages = np.zeros([self.Nsteps, len(V_node)], dtype=np.float32)
 
         # Initialize currents in battery models
         self.shm_i_app[0, :] = I_batt * -1
 
+        # Initialize the node voltages
+        self.node_voltages[0, :] = V_node
+
         # Step forward in time
         self.V_terminal = np.zeros(self.Nsteps, dtype=np.float32)
         self.I_terminal = np.zeros(self.Nsteps, dtype=np.float32)
@@ -263,6 +268,7 @@ def step_output(self):
         self.all_output["Pack current [A]"] = self.I_terminal[:report_steps]
         self.all_output["Pack terminal voltage [V]"] = self.V_terminal[:report_steps]
         self.all_output["Cell current [A]"] = self.shm_i_app[:report_steps, :]
+        self.all_output["Node voltage [V]"] = self.node_voltages[:report_steps, :]
         self.all_output["Cell internal resistance [Ohm]"] = self.shm_Ri[
             :report_steps, :
         ]
@@ -306,6 +312,7 @@ def _step(self, step, protocol, termination, updated_inputs, skip_vcheck):
             I_app = I_batt[:] * -1
             self.shm_i_app[self.global_step, :] = I_app
             self.shm_i_app[self.global_step + 1, :] = I_app
+            self.node_voltages[self.global_step, :] = V_node
             self.inputs_dict = lp.build_inputs_dict(I_app, self.inputs, updated_inputs)
         # 06 Check if voltage limits are reached and terminate
         if np.any(temp_v < self.v_cut_lower):
@@ -318,6 +325,10 @@ def _step(self, step, protocol, termination, updated_inputs, skip_vcheck):
         if np.any(v_thresh < 0) and np.any(v_thresh > 0):
             # some have crossed the stopping condition
             vlims_ok = False
+        if self.node_termination_func is not None:
+            if self.node_termination_func(V_node):
+                lp.logger.warning("Node voltage limit reached")
+                vlims_ok = False
         if skip_vcheck:
             vlims_ok = True
         # 07 Step the electrochemical system